1. Field of the Invention
The present invention relates generally to the extraction or separation of cut or partially cut pieces or parts from a sheet of material, having the pieces or parts cut into the sheet by various methods such as, steel rule die, male female tooling, laser, traveling knife and water jet.
2. Description of the Prior Art
In the converting industry, and in particular in the flat stock blanking and die cutting industry, it is a common requirement to separate cut parts from the sheet, web or blank from which the parts have been cut. Various methods are used to effect this separation.
In low volume operations, it is a common practice to separate the parts from the sheet or web manually, i.e., the sheet or web is twisted and the parts are poked out by hand to break the parts out of the scrap matrix and drop them in a collection vessel. The requirement for manual labor, the slowness of the process and the inability to maintain part sequence are deficiencies in this commonly used separation method.
In higher volume cutting operations, it is common practice to position the recently cut sheet or web in a knock-out station, wherein male/female knock out members are actuated to blank or knock the parts out of the sheet or web and onto a catch table. The scrap matrix is then removed from the blanking or knock-out station and discarded. Knock-out stations effectively remove parts from the scrap matrix, but their shape is job specific requiring a uniquely contoured male/female blanking or knock-out station for each cut line pattern. A second deficiency of knock-out stations, in particular for sheet processing, is their inability to shingle the parts in a shingle stack after knocking them out. This is because sheet edges are used to position sheets in the knock-out station and thus the entire sheet must be blanked or knocked out at one time. The inability to shingle stack parts makes the processing of sequential parts, such as membership cards, impractical with a knock out procedure, and the parts collection process, in general, clumsy.
Another method used to separate the scrap matrix from parts, are rotating xe2x80x9cstripper pin wheelsxe2x80x9d. In this method, rotating wheels equipped with barbed pins are positioned directly below the scrap web. As the material moves, the barbed pins penetrate the scrap web of the web or sheet continuously revolving to pull away the scrap. The parts keep moving straight ahead, while the scrap is pulled down and away from the parts. Once the scrap web, sheet or blank is pulled below the parts, the scrap web is scraped off the barbed pins, and dropped into a scrap bin. A shortcoming of this method is that relatively soft material into which the barbed pins can penetrate is required. Moreover, although scrap that runs parallel to the material feed direction can be stripped away, scrap cross bars (scrap or trim running perpendicular to the material feed direction) cannot be stripped away.
Heretofore various analogous and non-analogous systems and structures for extracting cut or partially cut parts from a sheet, web or blank have been proposed. Examples of previously proposed part extractors are disclosed in the following U.S. patents:
The Baumgartner U.S. Pat. No. 2,655,842 discloses a deflector plate for deflecting downwardly the waste sheet from a sheet of die cuts.
The Deslauriers U.S. Pat. No. 3,889,863 discloses an edge roller and a deflector plate for deflecting a die cut sheet.
The Deutsch et al. U.S. Pat. No. 3,948,020 teaches a roller-shaped deflector or looping element. When a lever is pivoted counterclockwise, as shown in FIG. 2 or FIG. 3 of this patent, the deflector moves to a second position and causes a running web to form a loop in order to facilitate the replacement of the running web with a fresh web.
The Lang U.S. Pat. No. 4,047,474 discloses a stripping station for removing waste portions which are apparently removed by a punching operation or a suction operation. Then, a leading edge portion is engaged by a gripping bar.
The Martorano U.S. Pat. No. 4,096,981 discloses an apparatus for stripping a continuous web of material from the marginal edge of a body. The stripping apparatus includes a pivotable deflecting plate located above the path of movement of the continuous web for deflecting the trim from the die cut piece surrounding a die cut piece in the web and directing it toward a pair of separating rollers which then pull the trim downwardly.
The Aquilla U.S. Pat. No. 4,109,842 discloses projection structures for engaging a side edge of a die cut sheet and moving it downwardly, as best shown in FIG. 3 of this patent.
The Deslauriers U.S. Pat. No. 4,467,948 teaches a stripping belt, as best shown in FIG. 6 of this patent, for engaging and removing trimmed waste from a die cut sheet.
The Chmielewski U.S. Pat. No. 4,197,938 teaches a similar stripping belt for removing a waste portion of a die cut sheet.
The separating apparatus in the Mineki U.S. Pat. Nos. 5,219,108 and 5,470,004 teaches a press roller that rotates around the circumference of a rotation roller to separate a scrap web from a cut part and a separation helping plate.
It is an object or feature of the present invention to provide a new and improved extraction system for separating cut or partially cut parts from a sheet.
Another object or feature of the present invention is to extract parts in such a manner that parts can be deposited and shingle stacked onto a conveyor.
Yet another object or feature of the present invention is to maintain the sequence of the sequentially formed products or parts subsequent to the extraction of the parts from a sheet.
A still further object or feature of the present invention is to extract parts of different shapes and sizes and different material thickness, rigidity and sizes without the need for adjustment of stripping or guiding fingers or knock-out elements specific to each part shape and size.
The foregoing and other objects or features of the invention are obtained with the method and apparatus described below.
In one preferred embodiment of the apparatus of the present invention there are provided input nip rollers which receive and drive cut sheets and an extraction roller which, when actuated, bends down the leading edge margin of a scrap web of a cut sheet around the circumference of the lower driven input nip roller, which sheet is otherwise held tangent to the nip point of the input nip rollers, with sufficient radius to cause the cut parts to separate from the scrap web, and which input rollers and extraction roller, as the driven input nip rollers drive the sheet, cause the cut parts, separated by the bend radius, to pass over the extraction roller and the remaining scrap web to pass between the extraction roller and the lower input nip roller. If desired, output nip rollers are positioned to receive the leading edge of the cut parts as the cut parts are separating from the scrap web to drive the cut parts along a line essentially tangent to the nip point of the input nip rollers and to assist in removing the cut parts from the sheet while transporting and depositing the parts in sequence onto a surface, such as a conveyor, in a shingle stacked manner.
As used herein, nip or nip point means the line of contact between adjacent nip rollers where the nip rollers engage and grip a sheet of material.
The apparatus may include motors, circuitry and software to time and actuate the functions of the nip rollers and the extraction roller. Alternately, the apparatus may be actuated manually such as with a foot pedal and hand crank.